Telephone system



March 22, 1932. R. TAYLOR ET AL TELEPHONE SYSTEM Filed Oct 15, 1950 2SheetsSheet l nueniur's R inald Ta 101" 59 Frank Ed EF' Cum n Mal-ch22,1932. R. TAYLOR ET AL TELEPHONE SYSTEM Filed Oct. 13', 2 Sheets-Sheet 2R frfivarsn nrs Fr i fm in" arm n Patented Mar. 22 1932 Uhliiifi STATESPATENT OFFICE REGINALD TAYLOR AND FRANK EDGAR COMYN, OF LIVERPOOL,ENGLAND, ASSIGNORS TO ASSOCIATED TELEPHONE AND TELEGRAPH COMPANY, OFCHICAGO, ILLINOIS, A

CORPORATION OF DELAWARE TELEPHONE SYSTEM Application filed October 13,1930, Serial No. 488,231, and in Great Britain October 17, 1929.

The present invention relates to telephone systems and is moreparticularly concerned with automatic systems employing finder switchesfor connecting a calling partys line with a first numerical switch.Finder switches of the two-directional type adapted to hunt freely inboth directions of motion have hitherto been, provided individually withcertain relays which are only employed when the switch is being set andserve no useful purpose during conversation. It will be appreciatedtherefore that if the relays which are used for controlling the settingof the switch could be arranged common to a plurality of switches then aconsiderable saving would result since fewer controlling relays wouldserve a group of switches than ifeach switch were. equipped with its ownindividual controlling relays. It is the object of the present inventionto produce an arrangement of this character in which switches of thebackwardly hunting type are controlled by a set of common controllingrelays associated with them during the setting operation over the wipersof a hunting switch.

According to one feature of the invention in a telephone system havingfinder switches adapted to hunt freely in two directions of motion arelay controlling the hunting operations is adapted to be temporarilyassociated with any one of a plurality of said finders.

According to another feature of the invention in a telephone systemhaving finder switches each provided with two magnets and adapted tohunt freely in two directions of motion, a relay adapted to transfer theoper-' ating circuit from one magnet to the other 1s adapted to betemporarily associated with any one of a plurality of said finders. Theinvention will be better understood from the following description oftwo methods of carrying it into effect, reference being had to thoseskilled in the art without departing from the spirit of the invention.

Referringnow to the accompanying drawings, Fig. 1 shows a finder switchhaving access to one himdred lines while Fig. 2 shows a finder switchhaving access to two hundred lines in which differentiation between anupper and a lower set of wipers is effected during the hunting motion ofthe switch. In the case of both figures it must be mentioned that thevertical bank marking arrangement and the subscribers line relays andsubstation circuits are not shown in detail but may be similar to thatshown and described in the Lomax and Saunders Patent No. 1,688,588granted 23rd October, 1928, while the emergency change-over arrangementsthere shown are also contemplated.

Referring now to Fig. 1, when a subscriber served by this finderoriginated a call, his line relay (not shown) operates and connectsearth to the vertical bank contact VB in order to mark the callinglevel, and at the same time causes relay A to operate in series withresistance 10. Relay A in operating its armature al extends earth by wayof armature Zcrl, winding of relay K, interrupter springs rim, windingof driving magnet DM of the finder allotter FA to battery. Relay Kthereupon operates over the circuit described and at armature 701extends earth via the resting contacts of armatures 01 and frl by way ofwiper 11 and bank contact of the finder allotter, resting contacts ofarmature 7L3, negative conductor to battery via one winding of the relay(not shown) of the associated group selector. The line relay operatesand completes a circuit for the release relay which in turn operate andconnects back earth over the release trunk conductor. At armature k2 apoint is opened in the hunting circuit of the driving magnet DM, and atarmature kaearth is connected via the winding of relay C, restingcontacts of armatures 7W2 and fret, wiper 16 and bank contact, verticalmagnet interrupter springs V, rotary magnet interrupter springs R, bankcontact and wiper 15, armature k3, winding of relay G to battery. RelaysC and Gr operate in this circuit, at armature 02 a shunt is placedacross armatures [Z672 and m, and at armature 01 the short-circuitacross the winding of relay FR is opened whereupon the relay operates inseries with the winding of the line relay of the group traced asfollows: earth, armature 71 3, armature g1, armature c3, and its frontcontact, wiper 14 and bank contact, rotary ofi-normalspringsRN,fwind1ngof vertical magnet VM to battery. Magnet VM will accordingly"operate to raise the sha ft and wipers the first step, at; theconclusion of which theofl-normalsprings N1 and NQ-operate and thevertical magnet V will then, at interrupter springs V, open thecircuitof relays C and G. Relay C is slow-to-releas'e and maintainsarmature 02 operated butrelay G releases and opens the circuit of thevertical magnet at armature g1. Continued inter-action between themagnet and relay G will there'forecause the shaft and wipers to beraised to the marked level, whereat the vertical wiper VlV' will enbankcontact;c it will be noticed that relay G is then held operated over thevertical bank in a circuit which does not include the springs Va; RelayC it'must be mentioned is held operaited during the vertical steppingoperation oniaccountof the copper slug surrounding its core. .When themarked level is found, however, the windlng of relay C is maintainedopened and the relay'therefore releases, at armature cl connectsearth tothe right-hand terminal of relay KR, at armature 02 opens a point in itsown circuit and at armature 03 the stepping circuit is transferred fromthe vertical magnet by way of the wiper 13 and bankcontact to'the rotarymagnet RM. The rotary magnet energizes to-advance the wipers one stepintoengagement with the first set of bank contacts in the leyel'chosen,whereuponv the rotary off-normal springs RN are operated to disconnectthe circuit of the verticalmagnet VM, and prepare a circuit to theswitching relay H. I It must be meutioned'that when the rotary, wipersmake their initial rotary movement the vertical wiper VVV disengages thevertical bank contact and until the rotary magnet springs R becomeoperated at the conclusion of the rotary step, relay G is held operatedfrom earthby way of earth:

over armatures 02, 92 and 7W5. Relay G releases at the end of the firststep, at armature gilopens the circuit of the rotary magnet- RM, atarmature g2 opens a-point in its hold i-ng circuit and at armature 3removes the short circuit from'relay KR-whereup'on this relay operatesfrom earth via armature 01" to battery in series with resistance 17.Relay KR in operating prepares a further point in the circuit to relay Hat armature 707-3, opens the initial energizing circuit of relay K atarmature krl, and atarmature 701 2 opens a further point in the initialcircuit ofrel'ay C.

i If now the contacts engaged by the wipers are not those marked by theoperation of the line relay of the calling subscriber, wiper?" willencounter earth anda circuit'willagain be completed for relay G by wayof armature k2, interrupter springs R, bank contact and wiper 15',armature 7:3, winding of relay G to battery, whereupon the relay willoperate and again at armature g1 completethe circuit to, the rotarymagnet RM to cause the wipers to be accordingly moved onto the next setof bank contacts. This cycle of operations will continue until themarked line indicated by absence of earthpotential is reached whereuponthe short-circuit tothe switching relay H is removed and the relay thenoperates from earth at arm ature 7M3, wiper 1'4 and bank contact,operated springs RN, winding of relay H, springs R, bank contact andwiper 15, armature 703 winding-of relay to battery. Itmust be mentionedthat the latterrelay does not operate/tin this circuit due to the highresistance of relay H. counter earth on the corresponding vertical RelayH in operating completes a locking circuit from'earth over conductor Parmah re 7 bl. winding of relay 7 armature k5, winding of verticalmagnet VM to battery at armatures 71 3, and M; connects the negativeandpositive leads from the group selector through to the wipers of'thefinder, armature k3 also disconnects relay'FR, and atarmature k2connects earth fed oyer conductor P through "to the test wiper P inorder to mark the calling line busy and to effect the operation of thecut-off relay in the calling subscribers line circuit thereby clearingthe call-' inglineof its normal battery and earth connections.

be calling subscribers' 'li nerelay releases;

and the-marking earthen the vertical bank isremoved so thatrelay A willrelease unless otherlinesarecalling, Due to the release of relay FR thecircuitof relay KB 1' s opened atarm'atlure frl and ofrelay K atarmature fr2 whereupon these relays release. Relay K upon releasingconnects earth to its righthand terminal over armature 702. Whenrelay Kreleases a circuit may be traced from earth at the-operated springs N2,bank contaictandwiper 12, armature k2,- interrupter springs and windingofdriving magnet'DM- to, battery.- Accordingly the" wipers of the finderallotter are advanced one step in the search forthe next idle finderswitch; it will be seentha't relay K cannot again operate until such anidle finder is found,"owing to the earth connected to its right-handterminal over. off-normal springs of busy finders. Upon the release ofthe connection at the end of the conversation earth is removed from thereleasetrunk conductor thus causing relay Hto release,and acircuit iscompleted to the group selector release magnet and the finder i releasemagnet ZM from earth over conductor Z, operated springs N1, winding offinder switch release magnet ZM to battery. Hence it will be appreciatedthat the release of the group selector and the release of the finderswitch. take place simultaneously.

- Referring now more particularly to Fig. 2, this shows a switch similarto that already described but equipped with two sets of wipers arrangedto establish connection with 200 subscribers lines. It will be noticedthat in this case the interrupter relay G is of the well-known shuntfield type. hen a subscriber initiates a call, relays A and K areoperated as previously explained whereupon relay C is then operated in acircuit including the right-hand winding of the shunt field relay G.Relay C in operating completes similar functions to those hitherto, andin addition connects earth to the left-hand winding of relayG therebycausing the relay to operate, and at armature g1 toextend earth by wayof armature c3, wiper 14 and bank contact, springs RN to the verticalmagnet which operates thereby causing the shaft and wipers to beraisedone step. At the conclusion of the first vertical step the springs Vwill then operate and open the circuit of the.

rightwinding of relay G which will thereupon release and in turn openthe circuit of the vertical magnet VM.

It will thus be appreciated that interaction between relay G and thevertical mag net'will result in the shaft and wipers being raised to themarked'level whereat the vertical wiper VW will encounter earth on themarked bank contact thereby causing relay G to be held operated eventhough its original circuit via the winding of relay C is opened 7 atsprings V. Relay C will now release since its circuit is opened atsprings V and at armature 03 the stepping circuit .is transferred to therotary magnet R. Accordingly the rotary magnet energizes to advance thewipers into engagement with the first set of bank contacts in the levelchosen, whereupon the rotary oil-normal springs RN are operated in orderto prepare the switching circuit of relays HA and HB.

It will be noticed that upon the release of rotary relay C, relay G isheld operated from earth connected up by its armatures g2 and 574. Atthe conclusion of the first rotary'step, relay G is released due to thecircuit of its right-hand winding being opened at the rotary magnetsprings R, whereupon relay KR then operates and at armature 709 3 closesa point in the circuit of the switching relays HA and HB.

If now the firstset of contacts engaged by the wipers arenot thosemarked, wipers P1 left-hand winding of relay G to battery.

Consequently relay G again completes the circuit to the rotary magnet RMand thewipers are advanced onto the next set of bank contacts. Thiscycle of operations continuesuntil the marked line which is indicated'bythe absence of earth potential is reached, and assuming that. wiper P1encounters the marked li-ne, relay G cannot again operate since there isnow no circuit for its right-hand winding. Moreover the shortcircuitacross the winding of relay HA is now removed and this relay thereuponoperates over the circuit: earth at armature 1W3, wiper 14: and bankcontact, springs RN, winding of relay HA, armature M3, springs R, bankcontact and wiper 15, armature 703, right-hand winding of relay G tobattery. Relay HA upon operating completes a locking circuit for itselfas follows: earth fed over conductor P, armature b002, winding ofrelay'I-IA, armature 71,63, armature ital, winding of vertical magnet VMto battery. Furthermore at armature [m3 a point is opened in the circuitof relay HB, at armatures MA and ha5 the negative and positive leadsfrom the group selector are extended through to the wipers of the finderand relay FR is released, and finally at armature haG earth overconductorP is connected through to the test wiper of the finder in orderto mark the calling line busy and to efi'ect the operation of thecut-oil relayin the calling subscribers' line circuit which thereuponclears the calling line of its normal battery and earth connections.

Relay FR in releasing causes relays Kand KR to release and the wipers ofthe finder allotter FA are accordingly advanced onto the next set ofbank contacts. Upon the release of the connectio-nearth is removed.

from conductor P thereby causing relay HA to release. while at the sameinstant a circuit is completed to the finder switch release magnet fromearth over conductor Z and the switch is thus restored to normal in thewellknown manner. V

lVhat we claim as new and desire to secure by Letters Patentis:

1. In a telephone system, a group of finders each having primary andsecondary hunting movements, a steppingrelay common to all said finders,means for temporarily associating said relay with any one of saidfinders in response to a call, and circuits controlled by said relay foroperating the associated.

SUI

line, a steppingielay common to said finders,

finder in its primary and secondary hunting movements to find thecalling line.

2. In a telephone system, a group of finders each having primary andsecondary hunting movements, a stepping relay common to all saidfinders, means for temporarily associating said relay with any one ofsaid finders in responseto acall, circuits controlled by said relay foroperating the associated finder in itsvprimary and secondary huntingmovements to find the calling line, means for stopping the primarymovement in response to the finder encountering one potential and forinitiating the secondary movement, and means for stopping the secondarymovement in response to the finder encountering a different potential. li

! 3. In a telephone system, a group of finders each having primary andsecondary hunting,

movements, a stepping relay common to all said finders,'-means fortemporarily associating said'relaywith any one of said finders inresponse to a'call, circuits controlled by said relay for operating theassociated finder in its primary and secondary hunting movements to findthe calling line, test wipers in said finder, and means forsimultaneously testing over a pair of said wipers for a callinglineduring the secondary hunting move ment. v V

4. In a telephone system, a calling line, a

group of finders each having primary and secondary hunting movements tofind said line, a "switching relay in each finder for completing thetalking circuit to the calling an allo tting switch, wipers in saidswitch for 'allotting said finders for use in: turn, means for operatingsaid wipers to' connect said re-' lay with'one of said finders inresponse to a call, circuits controlled by said relay over said wipersfor operating the connected finder in its primary and secondary huntingmovements to find the calling line, a circuit including one of saidwipers for initially energizingithe'switching relay of the connectedfinder responsive to the finder finding the calling line, andanothercircuit for holding said switching relay energized completed re-'s'ponsive to its energization. I

T 5. In a'telephone system, agroup of finders each having primary andsecondary hunting movements, a stepping relay common to all i saidfinders, a rotary switch common to said finders, wipers in said switchfor-allotting said finders for use in turn,means for operating thewipers of said switch to connect said relaywith one of said finders inresponse to a call, and circuits controlled by said relay over saidwipers for operating the connected finder in its primary and sec-''ondary hunting movements to 'find the call- 7 ing line.

wipers of said switch "to connect said re-' lay with one of said findersin response to v a call, a circuit for each winding of said relay, meansfor energizingsaid relay only when both circuits'to both windings arecompleted, and circuits controlled by said relay over said wipers foroperating the con- 1 nected' finder in its primary and secondary huntingmovements to find the calling line.

7. In a telephone system, a group of finders having primary andsecondary hunting movements, 2, change-over relay common to all saidfinders for stopping the primary" hunting movement and forinitiatingwthe secondary hunting movement, astepping relay common to allsaid finders tor operating the finders in their hunting movements, an

allotting switch, wipers in saidswitchfor allotting any one ofsaid'finders for use in response to a call, and a circuit completedresponsive thereto for energizing said re lays.

8. In a telephone system, a group of finders having primary andsecondary hunting movements, a primary test wiper for each finder, aprimary magnet in each finder for operating the finder in 'its'primaryhunting movement, a secondary magnet in each finder for operating thefinder in its secondary hunting movement, an operating circuit for saidmagnets, a stepping relay common to all said finders, a change-overrelay common,

to all said finders, -means I for connecting said relays and circuitwithone of said finders and'for energizing said relays, means forintermittently operating said stepping relay to intermittently open-andclose said oper-;

ating circuit tooperate the magnets of said finder, means responsive tothe test wiper of said finder encountering a predetermined potential fordeenergizing said changeover relay, and means responsive to thedeenergization of said changeover relay for transferring said operatingcircuit from the primary magnet tothe secondary magnet of saidfinder.

9. In a telephone system, a group of finders having'primary andsecondary hunting movements, a stepping relay common to all saidfinders, a changeoverrelay common to all said finders, a rotary switch,wipers in. saidswitch for allotting said finders for use int/urn, meansfor operating the wipers of said switch to connect said relays with oneofsaid finders in response to a call, a circuit completed responsivethereto for energizing said relays, an operating circuit for operatingsaid finders in their primary and sec: ondary hunting movements, meansfor intermittently operating said stepping relay to iiitermittently openand close said operating.

circuit, and means for deenergizing said changeover relay to transferthe operatmg circuit to stop the primary hunting move-. ment andinitiate the primary hunting ope plurality of finders having access tosaid line,

eration.

10. In a telephone system, a group of find-- ers having primary andsecondary hunting movements, a primary test wiper for each finder, achangeover relay common to all said finders, means for energizing saidrelay to initiate the primary hunting movement of an idle one of saidfinders, means responsive to the primary test wiper of saidfinderencountering a predetermined potential for stopping the primaryhunting movement of said finder and for deenergizing said relay, andmeans responsive to the deenergization of said relay for initiating thesecondary hunting movement of said finder.

11. In a telephone system, a calling line, a group of finders havingaccess to said line, a primary magnet in each finder for operating thefinder in a primary hunting movement, a secondary magnet in each finderfor operating the finder in a secondary hunting operation, an operatingcircuit for operating the magnets of said finders, a stepping relaycommon to said finders, means for connecting said relay with one of saidfinders, means for intermittently operating said stepping relay tointermittently open and close said operating circuit, and a change-overrelay common to said finders for transferring said operating circuitfrom the primary magnet to the secondary magnet of the connected finder.

12. In a telephone system, acalling line, a group of finders havingaccess to said line, a primary magnet in each finder for operating thefinder in a primary movement, a

secondary magnet in each finder for operating the finder in a secondarymovement, a stepping relay common to all said finders for controllingsaid magnets, means for temporarily associating said relay with any oneof said finders in response to a call on said line, and means controlledby said relay for operating the primary magnet and then the secondarymagnet of the associated finder to find the calling line.

13. In a telephone system, a calling line, a plurality of finders havingaccess to said line, a primary magnet in each finder tor operat ing thefinder in a primary hunting movement, a secondary magnet in each finderfor operating the finder in a secondary hunting movement, an operatingcircuit for operating the magnets of said finders, a change-over relaycommon to said finders, an allotting switch common to said finders,wipers in said switch for allotting said finders for use in turn, meansfor operating the Wipers of said switch to connect said relay with oneof said finders and to complete said circuit in response to a call, andmeans controlled by said relay for transferring said operating circuitfrom the primary magnet to the secondary magnet of the connected finder.

14:. In a telephone-system, a calling line, a

a primary magnet in each finder for operating the finder 1n a primaryhuntlng movement, a secondary magnet in each finder for operating thefinder in asecondary hunting movement, an operating circuit foroperating the magnets of saidfinders, a change-over relay commont-o saidfinders, means for temporarily associating said relay with any one ofsaid finders to complete said circuit in response to a call, and meanscontrolled by said relay for transferring said operating circuit fromtheprimary magnet to the secondary magnet of the associated finder.

15. In a telephone system, a group of finders having primary andsecondary hunting movements, a primary test wiper in each finder, achange-over relay common to said finders for changing the operation ofsaid finders from their primary to their secondary hunting movements, astepping relay common to said finders for operating the finders in theirhunting movements, an allotting switch, wipers in said switch forallotting any one of said finders for use in response to a call, acircuit completed responsive thereto for energizing said relays in aseries circuit including wipers on said switch, means responsive to thetest wiper of said finder encountering a pre determined potential duringthe primary cuit, a change-over relay for transferring said circuit tochange the operation of said finder from its primary to its secondaryhunt ing movement, means for energizing said relays responsive to a callto close said operating circuit to operate said finder in its primarymovement, means responsive to said wiper encountering a predeterminedpotential for deenergizing said change-over relay, circuits fortemporarily maintaining said stepping relay energized before and afterthe deenergization of said change-over relay, and

means responsive to the deenergization of said change-over relay forcompleting said operating circuit maintained by said stepping relay toinitiate the operation of said finder in its secondary movement.

17. In a telephone system, a calling line, a

" plur'ality of finders'having access to said line, 4 a pri'mary magnetin each finderfor operating T the finder in az -prima-ryhuntingmovement, a .7

secondar magnet in each finder for oper'at ing the nder in a'secondaryhunting move- *I'n'en't, an allotting switch common to said finders,wipers in said switch for allotting said finders for use in turn, meansresponsive "to ii -call for operating'sa d wipers to connect J'SafIdSWitCh with-one of said finders, a circuit including one of-saidfinders, a circuit includingo'neof sa'id Wipers for; operatingthepriwary magnet of the connected finder, means responsive to saidconnection for completing said circuit to operate said -primary magnet,

fa 'switching relay in'sai'd finder for completingthe telking cir'cu'itto the calling line, a

'circnitin cl-uding said one wiper for energiz ingsaid relay, andmeansresponsive to said findefr finding thecalling line for completing fsaid{last circuit to energize said switching relay;

Q "In testimony whereof we afiix our signatii'res.

--REGINALD TAYLOR. F-RANKEDGAR COMYN.

